Currently, cultivation using cages for Kappaphycus alvarezii was limited reported before. This study aims to reveal growth of K. alvarezii reared in floating cages and longline. The study was conducted in one of cultivation areas in Southeast Sulawesi, Indonesia. Total wet weight in kg was observed during 40 days. During the cultivation periods, the growth of K. alvarezii increased from 5 kg - 22,5 ± 1.40 kg by using longlines and from 5 kg - 38,8 ± 1,6 kg by using floating cage (Figure 1). During June, July and August, Specific Growth Rate (SGR) of K. alvarezii was 3.52, 3.53, 3.69 %.d-1 cultivated on floating cage and 2.41, 2.90, 2.43 %.d-1 cultivated on longline, respectively. Despite there are significant different in SGR of K. alvarezii cultivated during June-November between floating cage and longline were analyzed by Mann-Whitney Z test, considering confidence interval 0f 95 % (p ≤ 0.05).

Thallus look more dense and healthy during cultivation in floating cage and looks chipped and cut off due to consumed by fish for cultivate in August. Environmental factors observed during our experiment were related to the growth rates while the growth rate of K. alvarezii. During June and August, the current speed was high particular in evening (4 pm) 0.089 and 203 m/sec while temperature 27 and 29 ºC, respectively. Nitrate concentration was high during June, July, August and September, particular at evening (4 pm) 0.0789, 0.0632, 0.0085, and 0.0087 mg/L, respectively. Moreover, Phosphate concentration was high during May, June and September particular in morning (10 am) 0.0099, 0.0086 and 0.0087 mg/L. There are negatively correlated between growth rate of K. alvarezii in floating cage and longline with temperature and positively correlation with current velocity, salinity, nitrate and phosphate.